Miter attachment for a power saw

ABSTRACT

The device comprises a miter attachment for a power saw. An elongated base is formed of extruded aluminum stock to form a hollow housing of rectangular cross section. An intermediate portion of the base is provided with the standard miter cuts, 45* and 90* vertically and horizontally. The support for the power saw comprises a frame formed of spaced parallel supporting strips connected at their ends and pivotally mounted on the base so that the angular cuts fall between the strips. The outer edges of the strips are provided with integral semicircular guide plates. The base is provided with guide members which form slots for the edge of each plate to guide the frame in its pivotal movement. A small wedge shaped member is vertically slidably mounted in the housing and resiliently retained in the down position by a coil spring. The wedge member is located adjacent the outer perimeter of one of the guide plates so that when the wedge is raised, it is out of contact with the plate, but when the wedge is lowered by the spring, it engages the edge of the plate to hold it in position. Notches may be provided in the plate for locking the wedge at the 45* or 90* angles. A clamp is also mounted in the housing and provided with pivoted members beneath the frame for clamping the work in position. Since the work is clamped against the bottom of the frame, this also serves to hold the frame at the desired angle for the power saw.

United States Patent [191 Allaire MITER ATTACHMENT FOR A POWER SAW Joseph P. Allaire, 228 N.E. 22 Avenue, No. 4, Pompano Beach, Fla. 33062 Filed: Sept. 28, 1971 Appl. No.: 184,436

Inventor:

[56] References Cited UNITED STATES PATENTS 4/1953 Chappell 143/6 G 2,644,493, 7/1953 Hempe..... 3,380,492 4/1968 Konopka 143/6 G FOREIGN PATENTS OR APPLICATIONS 227,531 4/1960 Australia 143/66 Primary E xaminer-Donald R. Schran Attorney-Pierre Lesperance [57] ABSTRACT The device comprises a miter attachment for a power Int. Cl B27b 5/20 July 3, 1973 saw. An elongated base is formed of extruded aluminum stock to form a hollow housing of rectangular cross section. An intermediate portion of the base is provided with the standard miter cuts, 45 and 90 vertically and horizontally. The support for the power saw comprises a frame formed of spaced parallel supporting strips connected at their ends and pivotally mounted on the base so that the angular cuts fall between the strips. The outer edges of the strips are provided with integral semicircular guide plates. The base is provided with guide members which form slots for the edge of each plate to guide the frame in its pivotal movement. A small wedge shaped member is vertically slidably mounted in the housing and resiliently retained in the down position by a coil spring. The wedge member is located adjacent the outer perimeter of one of the guide plates so that when the wedge is raised, it is out of contact with the plate, but when the wedge is lowered by the spring, it engages the edge of the plate to hold it in position. Notches may be provided in the plate for locking the wedge at the 45 or 90 angles. A clamp is also mounted in the housing and provided with pivoted members beneath the frame for clamping the work in position. Since the work is clamped against the bottom of the frame, this also serves to hold the frame at the desired angle for the power saw.

11 Claims, 6 Drawing Figures PATENTEU JUL3 I975 MITER ATTACHMENT FOR A POWER SAW My present invention relates to the carpentry art, and more particularly to a miter attachment for a power operated hand saw.

Te principal object of the present invention is to provide a miter attachment for a power saw.

Another object of the present invention is to provide a miter attachment suitable for the do-it-yourself householder for the portable power saw.

A further object of the present invention is to provide a miter attachment for a power saw which is simple and easy to operate and adjust for the angle of cut.

Another object of the present invention is to provide a miter attachment for a power saw which is simple in construction and easyand economical to manufacture and assemble.

With the above and other objects and advantageous features in view, my invention consists of a novel arrangement of parts, more fully disclosed in the detailed description following, in conjunction with the accompanying drawings, and more particularly defined in the appended claims.

In the drawings,

FIG. 1 is a plan view of a miter attachment embodying my present invention;

FIG. 2 isa side elevation thereof;

FIG. 3 is an end view of the miter attachment as seen from the'left in FIGS. 2;

FIG. 4 is a smaller view similar to FIG. 1 with the frame turned to a 45 angle;

FIG. 5 is an enlarged section taken on line 5-5 in FIG. 2 showing a lock mechanism forming part of the invention;

FIG 6 is a fragmentary enlarged section showing the lock mechanism as seen from the right in FIG. 5.

With the increase in population and home ownership, the do-it-yourself business has greatly increased. Most home owners have full sets of tools for doing the jobs around the house. The tools usually include power drills and power saws. One of the most popular power saws, for example, is a Black & Decker No. U336 6% inch hand power saw. While the average householder learns to use his power equipment, accuracy is always a problem. While miter boxes have been provided for accurate cuts on a hand saw, there has been no miter attachment for a power saw. The present invention is designed to provide a miter device for a power saw which permits accurate cuts with a power saw at any desired angle.

Referring more in detail to the drawings illustrating my invention, the device. comprises the supporting base 10 and the power saw guiding and supporting frame 1 1. The base 10 comprises an elongated, hollow, housing preferably of extruded aluminum, and of rectangular cross section. As shown in FIGS. 3 and 5, the base 10 comprises a short bottom wall 12, a similar short top wall 13, and side walls 14 and 15, all integrally connected. The side walls 14 and 15 are provided with openings 16 in appropriate places along the length of i the base to permit access for assembly and adjustment.

As can be seen in FIGS. 1 and2, the base 10 is provided forwardly of the center part, with a plurality of standard miter cuts 17 for the passage of the saw blade. These include the straight vertical cuts, 45 cuts, and angular cuts as in FIG. 4. When the work is locked in position, the saw will make the desired angular cut. The cuts 17 form apertures through the side walls 14 and l5 which define a channel or passage extending transversely through the base.

The frame 11, which supports the saw, is pivotally mounted on the base 10 as shown in FIGS. 1 and 2. A pair of spaced parallel flat supporting strips 18 are locked in proper position by the generally U-shaped supports 19 at each end. The supports 19 are vertically positioned and have their ends provided at the top edges with horizontal portions 20 on which the strips 19 are locked by the screws 21. The U-shaped supports 19 therefore define apertures which align with the aforementioned channel for passage of a saw from one end to the other of the strips. Now viewing FIG. 1, the supporting strip 18 to the left is provided with an integral semicircular plate member 22 which may be cut out at 23 to reduce the amount of metal and provide visibility. The plate 22 acts as one of the guides for the strips 18. The otherv guide extends opposite the plate 22 integrally from the strip 18 to the right. This comprises a semicircular strip 24 extending from end to end of the adjacent supporting strip 18, and having a central supporting bar 25, leaving the openings 26. Note that the guide strip 24 is on a longer radius than the plate 22. This is so because the pivot point for the frame 11 is at 27 at the extreme left edge of the left strip 18 and the arc-shaped portion formed by the lateral perimeter of the strips are concentric with the axis of the pivot 27.

Te pivot point 27 is the top of a bolt 28 which extends through the base and engages the bottom wall 12 of the base 10. At the forward end of the base 10, a guide member or clip 29 is screwed onto the top wall 13 and is provided with an extended portion 30 which frictionally engages the top adjacent edge of the guide strip 24.

-On the other side, a similar guide member or clip 31 is screwed onto the top wall 13 and is provided with the extended portion 32 which engages the adjacent edge of the plate 22. This arrangement permits pivotal movement of the support 11 at the point 27. The plate 22 and strip 24 guide and retain the frame 11 to poisition the inner edges of the strips 18 at the proper angular relation to the cuts 17 to guide the saw therethrough while the saw is supported onto the strips in projection into the aforementioned transverse channel for operative lengthwise displacement into the latter from one side to the other of the base.

It is necessary, of course, to make sure that the frame 11 is held at the desired angle to the base 10 during the movement of the saw. This is accomplished in two ways. First, I provide a wedge member 33 in the form of an elongated vertically positioned plate, see FIG. 6, having a vertical slot 34 adjacent the bottom end toward one side edge. A pivot bolt 35 extends through the slot 34 to lock the member 33 to the base 10, but permits limited vertical movement of the member 33. The top of the member 33 extends upwardly through a slot in the top wall 13. The back edge of the member 33 is provided with a pin 36. A coil spring 37 is mounted in the base 10 with one end attached to the bottom at 38 and the other end attached to the pin 36. This resiliently retains the member 33 in the down position. The rear edge of the member 33 is cut out to form the angular edge 39 terminating in a shoulder 40. A largeopening41 is provided adjacent the top end of the member 33- for easier manual grasping.

Now viewing FIGS. 1 and 4, the plate 22 is provided with a plurality of notches 42, 43 and 44 in spaced relation around the perimeter thereof. The member 33 is placed close to the edge of the plate 22 and in its lowermost position the edge 39 engages the edge of the plate 22 to frictionally hold it in position. By pulling the member 33 upwardly against the action of the spring 37, the frame 11 can easily be pivotted around the pivot point 27 to the desired angle. Now the member 33 is released and pulled downwardly by the spring 37. The wedge surface 39 will clamp against the perimeter of the plate 22 and hold it in proper relation to the base 10. However, the most used angles are either 90 or 45. The central notch 43, see FIG. 1, is so positioned that when the supporting strips 18 are exactly at a 90 angle to the base 10, the wedge 33 will enter the notch 43 to positively lock the frame in this position. Now viewing FIG. 4, the frame 11 has now been pivotally turned to an angle of 45 to the cuts 17. In this position the wedge edge 39 of the member 33 will enter the notch 44. Similarly, if the frame 11 is pivoted in the pposite direction, the wedge will enter the notch 42 to hold the frame 11 in a 45 position in the opposite direction.

The above construction is designed to hold the frame 11 in its proper angular relation to the base 10. The work holding device constitutes another means of retaining the frame 11 in position. The work must be clamped against the base and up against the bottom surface of the frame 11. This clamping action will serve to further hold the frame in proper position. While any type of work holding clamp may be used, I have illustrated a screw type clamp shown in FIGS. 2, 3 and 6. A pivot bar 45 is mounted through the walls 14 and of the base 10 adjacent the bottom edge and rearwardly of the pivot point 27 as shown in FIG. 2. A clamping arm 46 extends upwardly from each end of the bar 45 with rubber tips 47 for clamping upwardly against the work and holding it tightly against the bottom of the adjacent supporting strip 18. Now, inside of the base, the pivot bar 45 is provided with a lever arm 48 which is pivotally connected by an elongated bar 49 to one end of a rack 50. Mounted in the base 10 is a small housing 51 through which the rack 50 extends as shown in FIGS. 2 and 6. A manually engagable handle 52 on top of the housing base 10, extends downwardly to a worm 53in the housing 51 which turns the gear 54in engagement with the rack 50. It is obvious, with the above arrangement, that turning movement of the handle 52 in one direction will move the rack 50 towards the right, and turning movement of the handle in the opposite direction will move the rack 50 to the left. This movement of the rack 50 is transmitted through the bar 49 to the lever arm 48, causing pivotal movement of the pivot bar 45 and its associated clamping arms 46. This will effectively clamp a piece of work beneath the supporting strip 18 to the left in FIGS. 1 and 2. This also serves to clamp the frame 11 in proper angular position.

A simple lever with a cam action may also be provided to accomplish the same clamping action. Various guide members are also provided. An adjustable guide strip 55 is mounted at the right of the supporting strip 18, see FIG. I. The strip 55 has a vertical flange 56 against which the saw is guided. At the left, an elongated bar 57 is mounted on the left strip 18 for a fixed guide at that edge. The guide bar 55 is adjustable sideways towards and away from the guide bar 57. The saw 58 slides between the guides, see FIG. 2. At the rear of the base 10, on the side walls 14 and 15, I provide a pair of vertically adjustable angle iron supports 59. These support the work extending from the clamp 46 and prevent sagging.

I have thus provided a simple means for guiding a power saw through a miter movement. The device is not attached to the saw, but forms a miter attachment sold with the saw. It is simple in construction, having a few readily assembled parts. Aluminum is the preferred metal because of its light weight and durability. The operation of the device is simple, the release of the member 33 permitting a quick and easy selection of the required angle. Other advantages of the present invention will be readily apparent to a person skilled in the art.

Finally, it should be noted that with the attachment of the present invention, mouldings are always sawed on the reverse side of the wood. This gives the visible front surface a perfect cut and finished appearance. The attachment of the present invention permits the angles to be adjusted to provide this cut.

I claim:

1. A miter device for a power-operated saw comprising an elongated base having aligned apertures through the opposite lateral sides thereof defining a channel extending transversely through said base, a frame pivotally mounted onto said base and including a pair of spaced-apart strips constructed and arranged for supporting a power saw thereon in projection into said transverse channel for operative lengthwise displacement into the latter from one side to the other of said elongated base, locking means constructed and arranged to releasably lock said frame at a selected angle relative to said elongated base, and a work clamping device constructed and arranged to adjustably clamp a piece of work against said frame and to cooperate with said locking means to lock said frame against rotation relative to said base.

2. A miter device as defined in claim 1, wherein said frame includes a pair of U-shaped bracket members transversely and upwardly underlying the opposite ends of said strips respectively with the ends of each U- shaped bracket members rigidly secured to the two strips respectively to rigidly connect one to the other and to define apertures arranged to be aligned with said channel for unobstructed passage of the saw from one end to the other of said strips.

3. A miter device as defined in claim 1, wherein said frame defines a pivot axis, said supporting strips are formed each with an arc-shaped portion concentric with said pivot axis and guiding members are mounted onto said base to operatively adjoin said arc-shaped portions and thereby pivotally restrain said strips onto said base.

4. A miter device as defined in claim 3, wherein said frame includes substantially semi-circular plates integrally extending from the opposite outer edges of said strips respectively and defining said arc-shaped portions, and said guiding members constitute guide clips mounted onto said base in slidable engagement with said plates.

5. A miter device as defined in claim 4, further including adjustable guide means mounted onto said strips and constructed and arranged to guide said saw along said strips.

6. A miter device as defined in claim 5, wherein said adjustable guide means includes a first guide bar fixedly secured onto one of said strips along the outer edge thereof and a second guide bar adjustably secured onto the other of said strips along the outer edge thereof and Y constructed and arranged for sideways displacement towards and away from said first guide bar, whereby to vary the spacing between said guide bars.

7. A miter device as defined in claim 1, wherein said frame defines an operatively lateral perimeter and is formed with spaced notches along said perimeter and said locking means includes a locking member pivotally mounted onto said base and arranged for pivotal movement towards and away from said perimeter and engagement into one of said notches and a spring connected to said locking member and arranged to bias the latter towards said engagement, whereby to nonrotatably hold said frame at angles of 45 or 90 to said base. 7

8. A miter device as defined in claim 7, wherein said locking member constitutes a plate extending upwardly relative to said base, having a manually engageable portion and an upward slot therethrough, a pivot extends transversely of said base through said slot, and one edge of said locking plate is slanted inwardly adjacent said perimeter and is arranged to downwardly and pivotally engage into anyone of said notches under the bias of said spring 9. A miter device as defined in claim 1, wherein said work clamping device includes clamping members outwardly projecting relative to said opposite sides respectively of said elongated base and constructed and arranged to selectively clamp a piece of work outwardly along any of said opposite lateral sides.

10. A miter device as defined in claim 9, wherein said work clamping device includes a handle rotatably mounted on said base and outwardly projecting therefrom for manual operation thereof, a gear track is geared to said handle to be linearly actuated therefrom, said clamping members include clamping arms and a crossbar is rigidly secured to said clamping arms for pivotal movement therewith and is connected to said gear rack and arranged to be rotated by the latter upon rotation of said handle.

11. A miter device as defined in claim 10, wherein said frame includes a pair of U-shaped bracket members transversely and upwardly underlying the opposite ends of said strips respectively with the ends of each U- shaped bracket members rigidly secured to the two strips respectively to rigidly connect one to the other and to define apertures arranged to be aligned with said channel for unobstructed passage of the saw from one end to the other of said strips, said frame includes substantially semi-circular plates integrally extending from the opposite outer edges of said strips respectively and defining arc-shaped portions, guide clips are mounted onto said base in slidable engagement with said plates, a first guide bar is fixedly secured onto one of said strips along the outer edge thereof, a second guide bar is adjustably secured onto the other of said strips along the outer edge thereof and constructed and arranged for sideways displacement towards and away from said first guide bar, whereby to vary the spacing between said guide bars, said frame defines an operatively lateral perimeter and is formed with spaced notches along said perimeter, said locking means includes a locking wedge plate extending upwardly relative to said base, having a manually engageable portion, and an upward slot therethrough, a pivot extends transversely of said base through said slot for pivotal movement towards and away from said perimeter, one edge of said locking wedge plate is slanted inwardly adjacent said perimeter and is arranged to downwardly engage into anyone of said notches, a spring is connected to said locking wedge plate and arranged to bias the latter towards said engagement to non-rotatably hold said frame at angles of 45 or 90 to said base, and the latter includes a body of hollow, rectangular, aluminum extrusion having a plurality of miter cuts extending transversely there- 7 through at angles of 45 and 90 thereto along said the saw.

channel for the passage of l I t i 

1. A miter device for a power-operated saw comprising an elongated base having aligned apertures through the opposite lateral sides thereof defining a channel extending transversely through said base, a frame pivotally mounted onto said base and including a pair of spaced-apart strips constructed and arranged for supporting a power saw thereon in projection into said transverse channel for operative lengthwise displacement into the latter from one side to the other of said elongated base, locking means constructed and arranged to releasably lock said frame at a selected angle relative to said elongated base, and a work clamping device constructed and arranged to adjustably clamp a piece of work against said frame and to cooperate with said locking means to lock said frame against rotation relative to said base.
 2. A miter device as defined in claim 1, wherein said frame includes a pair of U-shaped bracket members transversely and upwardly underlying the opposite ends of said strips respectively with the ends of each U-shaped bracket members rigidly secured to the two strips respectively to rigidly connect one to the other and to define apertures arranged to be aligned with said channel for unobstructed passage of the saw from one end to the other of said strips.
 3. A miter device as defined in claim 1, wherein said frame defines a pivot axis, said supporting strips are formed each with an arc-shaped portion concentric with said pivot axis and guiding members are mounted onto said base to operatively adjoin said arc-shaped portions and thereby pivotally restrain said strips onto said base.
 4. A miter device as defined in claim 3, wherein said frame includes substantially semi-circular plates integrally extending from the opposite outer edges of said strips respectively and defining said arc-shaped portions, and said guiding members constitute guide clips mounted onto said base in slidable engagement with said plates.
 5. A miter device as defined in claim 4, further including adjustable guide means mounted onto said strips and constructed and arranged to guide said saw along said strips.
 6. A miter device as defined in claim 5, wherein said adjustable guide means includes a first guide bar fixedly secured onto one of said strips along the outer edge thereof and a second guide bar adjustably secured onto the other of said strips along the outer edge thereof and constructed and arranged for sideways displacement towards and away fRom said first guide bar, whereby to vary the spacing between said guide bars.
 7. A miter device as defined in claim 1, wherein said frame defines an operatively lateral perimeter and is formed with spaced notches along said perimeter and said locking means includes a locking member pivotally mounted onto said base and arranged for pivotal movement towards and away from said perimeter and engagement into one of said notches and a spring connected to said locking member and arranged to bias the latter towards said engagement, whereby to non-rotatably hold said frame at angles of 45* or 90* to said base.
 8. A miter device as defined in claim 7, wherein said locking member constitutes a plate extending upwardly relative to said base, having a manually engageable portion and an upward slot therethrough, a pivot extends transversely of said base through said slot, and one edge of said locking plate is slanted inwardly adjacent said perimeter and is arranged to downwardly and pivotally engage into anyone of said notches under the bias of said spring.
 9. A miter device as defined in claim 1, wherein said work clamping device includes clamping members outwardly projecting relative to said opposite sides respectively of said elongated base and constructed and arranged to selectively clamp a piece of work outwardly along any of said opposite lateral sides.
 10. A miter device as defined in claim 9, wherein said work clamping device includes a handle rotatably mounted on said base and outwardly projecting therefrom for manual operation thereof, a gear rack is geared to said handle to be linearly actuated therefrom, said clamping members include clamping arms and a crossbar is rigidly secured to said clamping arms for pivotal movement therewith and is connected to said gear rack and arranged to be rotated by the latter upon rotation of said handle.
 11. A miter device as defined in claim 10, wherein said frame includes a pair of U-shaped bracket members transversely and upwardly underlying the opposite ends of said strips respectively with the ends of each U-shaped bracket members rigidly secured to the two strips respectively to rigidly connect one to the other and to define apertures arranged to be aligned with said channel for unobstructed passage of the saw from one end to the other of said strips, said frame includes substantially semi-circular plates integrally extending from the opposite outer edges of said strips respectively and defining arc-shaped portions, guide clips are mounted onto said base in slidable engagement with said plates, a first guide bar is fixedly secured onto one of said strips along the outer edge thereof, a second guide bar is adjustably secured onto the other of said strips along the outer edge thereof and constructed and arranged for sideways displacement towards and away from said first guide bar, whereby to vary the spacing between said guide bars, said frame defines an operatively lateral perimeter and is formed with spaced notches along said perimeter, said locking means includes a locking wedge plate extending upwardly relative to said base, having a manually engageable portion, and an upward slot therethrough, a pivot extends transversely of said base through said slot for pivotal movement towards and away from said perimeter, one edge of said locking wedge plate is slanted inwardly adjacent said perimeter and is arranged to downwardly engage into anyone of said notches, a spring is connected to said locking wedge plate and arranged to bias the latter towards said engagement to non-rotatably hold said frame at angles of 45* or 90* to said base, and the latter includes a body of hollow, rectangular, aluminum extrusion having a plurality of miter cuts extending transversely therethrough at angles of 45* and 90* thereto along said channel for the passage of the saw. 